Browsing by Author "Ishikawa, Shin-nosuke"

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    Hard X-Ray Constraints on Small-scale Coronal Heating Events
    (IOP Publishing, 2018) Marsh, Andrew J.; Smith, David M.; Glesener, Lindsay; Klimchuk, James A.; Bradshaw, Stephen J.; Vievering, Juliana; Hannah, Iain G.; Christe, Steven; Ishikawa, Shin-nosuke; Krucker, Säm
    Much evidence suggests that the solar corona is heated impulsively, meaning that nanoflares may be ubiquitous in quiet and active regions (ARs). Hard X-ray (HXR) observations with unprecedented sensitivity >3 keV are now enabled by focusing instruments. We analyzed data from the Focusing Optics X-ray Solar Imager (FOXSI) rocket and the Nuclear Spectroscopic Telescope Array (NuSTAR) spacecraft to constrain properties of AR nanoflares simulated by the EBTEL field-line-averaged hydrodynamics code. We generated model X-ray spectra by computing differential emission measures for homogeneous nanoflare sequences with heating amplitudes H 0, durations τ, delay times between events t N , and filling factors f. The single quiescent AR observed by FOXSI-2 on 2014 December 11 is well fit by nanoflare sequences with heating amplitudes 0.02 erg cm−3 s−1 99% confidence for all regions observed by either instrument.